Fig. 3. Slc37a2 localizes to a network of tubular secretory lysosomes.

a Endogenous localization of Slc37a2 in mouse bone marrow monocyte (BMM)-derived osteoclasts. Slc37a2 co-localizes with late endo-lysosomal markers (LAMP2, Rab7, and Arl8), but not with endosomes (Vps35), the endoplasmic reticulum (PDI) or the Golgi (GM130). Bar, 10 µm. b Pearson’s correlation coefficient (Rr) calculated from 10 osteoclasts pooled from two independent experiments. Data are presented as means ± SD. c Schematic of Slc37a2 structure and topology on SL membranes, with transmembrane (green cylinders), luminal cytosolic domains (black lines), N-linked glycosylation sites (blue boxes, N), and extreme C-terminus (magenta box) indicated. d Amino acid alignment of the far C-terminus for human SLC37A2 and mouse Slc37a2 isoforms (1 and 2) with lysosomal sorting motifs and alternative sequences indicated. Asterisks indicate conserved amino acids. e Confocal image of a mouse osteoclast cultured on glass co-microinjected with ^mCherry-Slc37a2 isoform 1 and ^emGFP-Slc37a2 isoform 2. Purple dashed line outlines the plasma membrane (PM). Bar, 10 µm (n = 5). f and g Representative confocal image of a live mouse osteoclast on glass microinjected with ^emGFP-Slc37a2 isoform 2 and pulsed with endolysosomal probes LysoTracker Red (f, n = 3) or DQ-BSA (g, n = 3). Line scans of the individual fluorescent intensities (arbitrary units, arb. units) correspond to the white diagonal line in the magnified views. Bars, 10 µm. h High-resolution live confocal image of a representative tubular SL bearing ^emGFP-Slc37a2 isoform 2 and housing Cathepsin K Magic Red (MR) within its lumen (yellow arrow). Bar, 2 µm. (n = 3). i Time-lapse confocal image of an osteoclast expressing ^emGFP-Slc37a2 isoform 2 before (−10 min) and after (+32 min) treatment with the microtubule disrupting agent nocodazole (10 µM). Bar, 10 µm (n = 3). Source data are available in the Source Data file. See also related Supplementary Movies 1–3.